1. Technical Field of the Invention
The present invention relates to a mechanism for manipulating an angle section in an insertion portion of an endoscope used for use in medial and other fields.
2. Description of the Related Art
An endoscope for medical or other use, generally, consists mainly of an insertion portion to be inserted into a body cavity and the like, a main operation unit to be connected at the base end of the insertion portion, and a universal cord which is extended from the main operation unit and is detachably connected to at least a light source device. The insertion portion is adapted to be inserted into the body cavity of a patient or the like for inspecting and carrying out diagnosis inside the body. Further, when necessary, a treatment can be performed by using forceps, a high-frequency treatment or other treating equipment to be inserted into the endoscope.
An operator manipulating the endoscope usually holds the main operating unit with one hand. In order to reduce a load on the operator operating the endoscope, the main operation unit is designed to be of reduced weight. To this end, the casing of the operation unit is formed of plastic, and the thickness of the casing is reduced as much as possible to expand the internal space with a small and compact shape. Since various members are installed within the operation unit, its casing is divided into several parts. These parts can be detachably assembled for the convenience of maintenance to those installed members, such as mounting, repair, inspection and replacement.
The casing of the main operation unit must have sufficient strength, at least part to which the manipulating or operating mechanism such as the later-described angle operation device is fixedly mounted. Therefore, the casing comprises a thick-walled main unit case portion to which is mounted the angle operation device and the like. The main operation unit has a main unit case portion and other portion or portions such as a holding case portion held by the operator. The holding case portion and the like are formed with thin-walled plastic, and may not be as strong as the main unit case portion.
A connecting member made of metal or the like mounted which is provided in the casing of the main operation unit is known in Japanese Patent Publication No. 2-43484. The known connecting member functions as a framework for the assembled parts of the casing to reinforce high strength. With this known configuration, the connecting member with the metal plate has one end fixed to the main unit case portion, and is extended to at least the inside of the holding case portion. The connecting member is fixed in a manner to exert a force to the holding case and the like to pull tightly, thereby abutting against the main unit case portion, and thereby increasing the overall strength of the casing of the main operation unit.
The insertion portion has a distal end section and an angle section, and further there is a bending section provided between the angle section and the operation unit. An endoscopic observing mechanism consisting of an illumination window and an observation window are provided at the distal end section. A treatment equipment outlet for introducing treatment equipment such as forceps is also provided at the distal end section as necessary. The angle section functions to turn the distal end section toward a desired direction by performing an angle operation to curve or flex it in vertical and horizontal directions by a remote control mechanism. Operating wires are provided to enable this angle operation. At least one pair of operating wires is provided at the upper and lower places in the insertion section for curving or flexing at a desired angle for the angle section vertically in the event that one operating wire is pulled and the other is pushed. Further, in addition to the pair each of the operating wires for upper and lower portions, another pair of operating wires is provided at the right and left places, thereby the angle section may be induced to curve vertically and horizontally. These operating wires are extended from the insertion portion to the inside of the main operation unit, and are connected to an angle operation device mounted to this main operation unit.
The angle operation device has at least one pulley, to which the base portions of the operating wires are wound, to pull and push the pair of the operating wires by rotation (one pulley uses a pair of operating wires, and two pulleys use two pairs of operating wires). A rotating shaft is coupled to the pulley. This rotating shaft is extended externally from the casing of the operation unit and an angle operation means, such as a knob or a lever, is linked thereto. The operator can control the direction of the angle section by manually manipulating the angle operating means using the fingers of the hand holding the operation unit.
The operating wires for angle operation are, for example, control cables, and a predetermined length of each operation wire is passed through the sleeve member. Thus, pushing and pulling the base end transmits the force thereof to the tip end. The sleeve member is generally flexible, such as a tightly coiled wire and flexible sleeve, or the like. However, at the rigid portion in the endoscope, for example, within the main operation unit, the sleeve member can be made of a hard pipe. Opposite ends of the sleeve member are to be securely fixed, and the operating wires are drawn out from both ends of the fixed sleeve member. The base end of the operating wire is wound around the pulley. The tip end of the operating wire is taken out from the sleeve member, which is provided at or before the angle section.
A great reaction force acts on the operating wires at the time of angle operation and this reaction force is to be received by the pulley. The ends of the sleeve member must be securely fixed, because the fixed portions of the sleeve member are affected by the reaction force. Also, the rotating shaft coupled to the pulley should be supported by the casing of the main operation unit in a stationary manner. The fixing means of the base portion of the sleeve member must also be held in a stable manner. Also, a means for preventing looseness of the operating wires is provided between the sleeve member and the pulley. The means for preventing looseness also moves together with the pushing and pulling operation of the operating wires, so a space is given between the base end of the sleeve member and the pulley to allow the removal of the means for preventing looseness in a predetermined range.
By situating the fixing means of the sleeve member apart from the pulley, the pulley should be connected to the main unit case independently from the edge of the sleeve member. In a conventional manner, the fixing means for the sleeve member is provided within the operation unit, and attached to the connecting member of the casing, which serves as a strength member.
The holding case portion receives a force toward the main operation unit. Also, when the insertion portion is inserted into the body cavity, the connecting member is caused to bend by the force acting to compress the operation unit, by the reaction force caused by the resistance and oppression upon inserting the insertion portion into the body cavity. When the connecting member is bent, the length of the operating wires is changed from the fixing means to the pulley, because the fixing means for the sleeve member is mounted to the connecting member of the casing. As a result, the angle section becomes unintentionally curved slightly even though the angle operating means is not manipulated, the amount of invalid stroke of operating the angle operating means is changed, and so forth.
Also, since the operating wires are exposed between the fixing means of the sleeve member and the pulley, the exposed portions of the operating wires may contact other installed members in the operation unit such as a light guide, thereby resulting in tangling and damage
Particularly, in the event that the means for preventing looseness provided to the operating wires is also exposed, the possibility of damage to the light guide formed of, for example, extremely fine optical fibers increases. Further, by separately providing and independently fixing the pulley, the sleeve member fixing means, and a means for guiding the operating wires, it becomes difficult to adjust their relative positional relationships.
In light of the above-mentioned drawbacks of the prior art, it is an object of the present invention to keep tension of the operating wires for performing angle operation constant even if the bending load or the like acts on the main operation unit.
It is another object of the present invention to maitain a stable positional relationship between the pulley and the sleeve member fixing means.
Further, it is an object of the present invention to allocate the operating wires within the operation unit in a facilitated manner, thereby allowing a smooth and suitable movement of the operation wires.
In accordance with the present invention for achieving the above-mentioned objects, there is provided a manipulation mechanism for an angle section of an endoscope, consisting of a main operation unit and an insert portion connected to the main operation unit, the insert portion having a distal end section connected with the angle section, adapted for manipulating to curve the angle section by pulling and pushing operation at least a pair of operating wires running throughout the insert portion and to introduced into the main operation unit; characterized in that the manipulation mechanism comprises: at least one pulley provided within the main operation unit, with the base of the operating wires wound thereupon; a pulley rotating shaft extended externally from a casing of the main operation unit to rotate the pulley; an angle operating means provided outside of the main operation unit and coupled to the pulley rotating shaft; a pulley supporting assembly fixedly held by the casing of the main operation unit, for supporting the pulley to be reciprocally rotated over a predetermined angle; a sleeve member provided within the main operation unit for passing through the operating wires from the pulley; a pipe holder fixedly mounted to the sleeve member; and a supporting rod connected at one end to the pulley supporting assembly and being fixed to the pipe holder at the other end.
It is desirable to have a wire cover detachably installed on the supporting rod to form a tunnel-shaped passage for running through the operating wires. The casing for the main operation unit can be composed of a main unit case portion to which at least the angle operation means is mounted, and a holding case portion which is assembled to the main unit case portion in a tightly abutting engagement by a connecting member. By so constructing, the fastener member and the supporting rod can be kept apart from the connecting member.
These and other objects, configurations, and advantages of the present invention will become more apparent from the embodiments described below with reference to the drawings. It is needless to say that the present invention is not to be interpreted so as to be restricted to these embodiments.